Safe Speeds

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To expand on one of the components of the Safe System, “Safe Speeds” have been suggested since there is a direct correlation between vehicle speed and the likelihood of crash occurrence, seriousness of injury and the odds of a fatality. For example, the risk of a pedestrian fatality for different vehicle speeds is shown adjacent. https://apps.who.int/iris/rest/bitstreams/52184/retrieve

As a result, speed management measures, including road design, speed limits and the use of automated enforcement are critical pieces of a successful road safety program. Speeding (i.e., driving too fast for conditions) can result in a loss of control, failure to stop in time, and more serious injuries or deaths in the event of a collision. Some of these measures are described below under “countermeasures”.

Prevalence of Speeding:

In 2021, according to Transport Canada’s National Collision Database, 25% of fatal collisions involved speeding according to police investigations. This percentage was slightly higher than the percentage in 2017 (23%). Speeding in fatal collisions was more common on motorways, where speed limits were over 70kph, between midnight and 6:00am, on weekends, in collisions involving light utility vehicles, among male drivers, and drivers aged 15 to 24. In 2020, about 25% of fatalities involving speeding, involved alcohol and 4% involved drugs.

Pedestrian Survival Rate by Vehicle Speed

Approximate survival rate if hit by a vehicle at various speeds
Source : Version adaptée du taux de survie des piétons en fonction de la vitesse du véhicule, par l’Organisation mondiale de la Santé, 2009 (https://www.edmonton.ca/transportation/traffic_safety/residential-speed-limits-faq). © 2021 par City of Edmonton.

Countermeasures:

The goal of countermeasures is to reduce speeds to levels where any impact that occurs can be tolerated by the human body. One effective way to achieve this goal is through road network planning and design. On major roads, this may include narrower lanes, roundabouts, and median barriers that influence drivers to voluntarily reduce their speed. In residential areas, municipalities have implemented such measures as speed bumps or humps (humps being less aggressive), narrowed streets, and curb extensions. Some municipalities are reducing speed limits in residential areas, school zones and high-pedestrian areas to 30 or 40 km/hr.

Enforcement is an important and necessary measure for speed management. In many countries, speed enforcement has significantly evolved over the past 10 years. There has been a general increase in the focus of enforcement efforts and the increasingly widespread introduction of automatic speed control (e.g., speed cameras), which gives a new dimension to the enforcement effort. If undertaken appropriately, speed enforcement can be a very powerful deterrent that contributes directly to reducing the incidence of speeding and consequently, the frequency and severity of crashes.

Multiple research studies suggest that injury crash reductions can be in the range of 20 to 25 per cent at conspicuous, fixed speed camera sites, and there is also evidence of significant crash reductions through mobile enforcement programs in the United States

https://www.cdc.gov/motorvehiclesafety/calculator/factsheet/speed.html.

Some cities are mounting digital signs which display a driver’s speed as they approach the sign in order to encourage them to slow down. Local governments, as well as provincial/territorial governments, conduct awareness campaigns to remind drivers that speeding is dangerous.

For more information:

Safe Speeds FAQs:

What per cent of all traffic fatalities are speed-related?
In 2021, 24.7 percent of fatal collisions in Canada involved speeding.
How can pedestrian deaths be sharply reduced? And to what extent?
A reduction in vehicle speed from 50 km/hr to 30 km/hr reduces the average probability of a pedestrian fatality from approximately 80 percent to approximately 10 percent.
How can the authorities manage traffic speed?
The management of speed can be achieved through the use of appropriate speed limits, provision of road infrastructure to support these limits, police enforcement, education and community engagement, and vehicle and other technologies. A combination of these approaches is recommended. Speed management should occur as part of a structured, consistent approach that covers the entire road network of interest. However, in many instances, localized reductions to speed limits may be required, often in response to local safety issues.
What is a safe and appropriate speed?
To be safe and appropriate, speed limits need to be set in reference to the road users that are likely to be present, the protection offered by vehicles and road design, and the effects of road, traffic, and weather conditions. Speeds should be managed based on our understanding of the known limitations of the forces that the human body can withstand during a crash. Pedestrians can typically survive impact speeds of around 30 km/hr, above which the chance of survival decreases dramatically. Similar impact speed thresholds are likely to apply to other unprotected road users such as motorcyclists and bicyclists. At intersections, side impacts at or below 50 km/hr are survivable for automobile occupants. For head-on crashes, occupants of modern vehicles with good quality safety features can generally survive an impact at 70 km/hr with another vehicle of equal mass. Achieving speed limits that eliminate deaths and serious injuries should be the ultimate objective for road safety.
What is the role of enforcement in speed management in urban areas?
Enforcement is an important and necessary measure for speed management. In many countries, speed enforcement has significantly evolved over the past 10 years with a general increase in the focus of enforcement efforts. Automatic speed control adds a new dimension to the enforcement effort and has become increasingly widespread. When undertaken appropriately, speed enforcement can be a very powerful measure that contributes directly to reducing the incidence of speeding and, consequently, the frequency and severity of collisions.
Can vehicle technology help drivers control their speed?
Vehicle technologies can play a significant role in speed control. Speedometers were the first devices installed in this regard. Major advancements in automotive technology have greatly enhanced road user safety through automatic speed management. Modern vehicles are equipped with devices that assist drivers select appropriate speeds, such as speed limiters, or adaptive cruise control that adjusts driving speeds to always maintain safe gaps with the traffic ahead.

For further information, go to https://www.itf-oecd.org/sites/default/files/docs/06speed.pdf.